AB with "little sister" and "uncle"

We call all of our adult friends "auntie" and "uncle" (with or without first name following "ayi" and "shu shu"...

These two are so cute together and are finally starting to really play together. When we go downstairs, AB points to their door and says "meimei!" (little sister). Her ayi (nanny) said that yesterday she was pounding on their door yelling "MEIMEI!" at one point. Thought that was kinda funny.